The invention is directed to a phased-array antenna in which transmitted energy from a primary feed system is radiated through free space as a primary wave to a plurality of first radiator elements, preferably arranged in rows and columns in a single plane, where they are received, conducted over a plurality of phase shift elements which may be electronically controlled and which convert the primary wave into a planar wave, and which in addition, effect a desired beam deflection, and subsequently emitted by a plurality of second radiator elements, in the form of a planar wave. The second radiator elements likewise preferably are arranged in rows and columns in a single plane and are correspondingly disposed with respect to the first radiator elements. In like manner, receiving energy may pass, in the opposite direction, along such path.
In a radiation-fed, electronically controlled antenna, the high frequency power produced in a transmitter is conducted over a primary feed system, by radiation, to the antenna elements at the aperture. The aperture comprises a plurality of antenna elements, for example, dipoles, which are usually arranged on a flat surface of specific geometric configuration.
In order to produce the directional operation of the antenna, the differences in transit time resulting from different distances of the individual and planar elements from the primary feed system must be compensated, which may be termed "focusing". The deflection of the antenna beam is derived by means of a phase delay which is linearly dependent upon the coordinates of the aperture, and of the currents in the individual antenna elements. The phase is usually controlled by electronically variable phase shift elements.
The focusing of the primary beam may be effected either through electrical delay lines which are of different length and are individually calculated and produced for each antenna element, and which are subsequently connected to the phase shift elements, or else in the phase shift elements per se. The adjustment or control of the phase shift elements comprises two parts, one of which is formed by the required focusing phase, and the other the deflection phase required for a specific beam direction. The adjustment of the phase shift elements is calculated for all the antenna elements in conjunction with a so-called phase calculator. In a phase controlled antenna arrangement of the irradiation type the radiator elements are disposed at both sides of the antenna aperture with the primary wave emitted from the primary feed system impacting against a wall of first radiator elements, the so-called collector radiator elements, and connected to each of these elements is a phase shift element and possibly also a delay line, whereby the high frequency current at this point is influenced with respect to its phase in accordance with the desired beam deflection and the required focusing. The second radiator elements, the so-called emitter radiator elements, are connected to the other side of the respective phase shift elements with the second radiator elements likewise forming a wall which, in their entirety, emit a planar wave in the desired direction of deflection.
All of the known phased-array antenna arrangements of this type have the characteristic that they permit a beam deflection of x 0.degree. to approximately .+-.45.degree. (maximum .+-.60.degree.) in relation to the normal of the surface formed by the emitter radiator elements. If all directions of a full azimuth angle range of 360.degree. is to be employed, generally the relatively high outlay of four such flat antenna arrangements will be required, each displaced by 90.degree. in relation to one another.
The monitoring of the full azimuth range also can be achieved by the employment of cylindrical or conical phased-array antenna arrangements which, however, entail extremely complex operating devices merely because it always is necessary to switch off the radiator elements facing in a direction opposite to that from the instantaneous beam direction.